I have the same suspicion, Vlad. This was theorizing on my part :-) I had to implement something like this for a very different reason, and so discovered the downside (IMO) of doing clever things with mouse move. I try to stay away from stuff like this. It's probably just me, but it's all I can do to keep up with testing the hardcore, integral part of my apps.

>This is a good trick, but you'll never be sure that the shape will get a mousemove event in all cases. Am I right?
...snip